Samples made from natural bismuth were exposed in 60 MeV end-point bremsstrahlung beam. In this paper, a simple model for determination the share of two ways of 203 Pb formation: by the decay of 203 Bi, produced in 209 Bi(γ,6n) 203 Bi reaction and by 209 Bi(γ,p 5n) 203 Pb reaction is described. The method employs the ratio of 203 Pb and 203 Bi nuclei numbers and activities at the end of the exposure as the input value. This ratio was estimated from gamma spectra measured after irradiation of natural Bi sample. It was found that the rate of production of 203 Pb by 209 Bi(γ,p 5n) 203 Pb reaction is about 6% of the 203 Bi production rate in the 209 Bi(γ,6n) 203 Bi reaction. Obtained result is compared with TALYS based estimation.